A method for preparing high-efficiency perfluorononenyl ether

Abstract

The invention provides a method for preparing an efficient perfluorononenyl ether, and relates to the technical field of organic synthesis. The method comprises the following steps: in the presence of a phase transfer catalyst, using a KOH aqueous solution as a base, adding a hydroxyl compound, slowly adding a hexafluoropropylene trimer to react, and separating and purifying to obtain the perfluorononenyl ether. In the presence of a phase transfer catalyst, a green reaction system using water as a reaction medium and an inorganic base as an acid absorber overcomes the drawback of low reaction efficiency in a heterogeneous reaction process, and the obtained perfluorononenyl ether has a high yield and a high raw material conversion rate.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for preparing high-efficiency perfluorononenyl ether. Background Art

[0002] Surfactants are known as "industrial MSG" and occupy a particularly important position in various fields such as chemical industry, oil extraction, textile, food, transportation, agriculture, metallurgy, building materials, etc. Fluorine-containing surfactants are special surfactants. Due to the high electronegativity of fluorine element, small van der Waals radius, and strong carbon-fluorine bond energy, fluorine-containing surfactants have high surface activity, high chemical stability, high thermal stability and water and oil repellency. Non-ionic fluorine surfactants are less affected by electrolytes and acid-base environments, are easily soluble in organic solvents and water without ionization, and have good compatibility with hydrocarbon surfactants. Therefore, they have received widespread attention and have good application prospects.

[0003] The dimers and trimers obtained by the polymerization of hexafluoropropylene are very useful chemical raw materials, and many fluorinated surfactants can be derived. The hydrophobic perfluorocarbon chain of hexafluoropropylene oligomers is highly branched, which adds some special physical properties compared with general straight-chain perfluoro surfactants. It can be used alone or in combination with other surfactants, so it can play a unique role in detergents, plastics, coatings, textiles, leather, petroleum, electronics, pigments and other fields. For example: the perfluoroalkyl ether produced by the reaction of hexafluoropropylene oligomers with phenol can be reacted with fuming sulfuric acid to produce sulfonate-type fluorinated surfactants. The reaction of perfluoroalkyl ethers with chlorosulfonic acid can introduce sulfonyl chloride groups on the benzene ring, and further reactions can be used to produce various fluorinated surfactants. The fluorinated surfactants prepared from hexafluoropropylene oligomerization derivatives have the characteristics of reducing interfacial surface tension and directional adsorption in solution and forming micelles, which makes them widely used in washing, plastics, metals, coatings, textiles, leather, household products, petroleum products, electronics industry and other fields.

[0004] For example, Chinese patent 201410006153.7 reported the use of triethylamine and [bmim]OH alkaline ionic liquid as catalysts to catalyze the reaction of hexafluoropropylene trimer and acrylic acid hydroxyalkyl ester to prepare the corresponding acrylic acid perfluoroalkenyl alkyl ester product. By polymerizing the fluorinated acrylate, a series of high-performance fluorinated coatings with waterproof, oil-proof and dust-proof properties can be prepared.

[0005] Chinese patent 201410647872.7 reported that perfluorononene phenyl ether was prepared by addition-elimination reaction of hexafluoropropylene trimer and phenol in tetrahydrofuran solution under the action of potassium carbonate, and then a series of amphoteric surfactants containing perfluorononene groups were prepared by chemical transformation of the benzene ring in the phenyl ether. In this type of fluorinated surfactant, the use of materials with toxic components such as PFOS (perfluorooctane sulfonic acid) or PFOA (perfluorooctane carboxylic acid) was successfully avoided.

[0006] Japanese patent JP2006342088 reported that perfluoropropylene trimer undergoes addition-elimination reaction with various alcohol compounds in DMF and potassium tert-butoxide system to prepare a series of perfluorononenyl alkyl ether compounds. Such compounds can be used as high-performance fluorinated ether solvents and are widely used in many aspects of the national economy.

[0007] However, among the reported conversion reaction conditions of hexafluoropropylene, some use organic solvents (such as tetrahydrofuran, DMF, etc.) as reaction media, some use triethylamine as a reaction base, and some use ionic liquids as a base to promote the reaction. These conditions add a lot of difficulties to the cost control of the product production process and the treatment of three wastes. Moreover, the preparation of perfluorononenyl ether by hexafluoropropylene trimer is a heterogeneous reaction process. Since the two reactants are in two phases, the speed at which the catalytic reaction can occur is very slow. Therefore, it is necessary to add a transfer catalyst to transfer the reactants in one phase to another phase to speed up the reaction rate.

[0008] Therefore, developing an efficient preparation method of perfluorononenyl ether is the research focus of the personnel in this field. The present invention provides a green reaction system in the presence of a phase transfer catalyst, using water as a reaction medium and an inorganic base as an acid absorber, and the obtained perfluorononenyl ether has a high yield, a rapid reaction, and a high raw material conversion rate. Summary of the invention

[0009] In view of the above problems, the present invention provides a highly efficient method for preparing perfluorononenyl ether.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] On the one hand, the present invention provides a method for preparing an efficient perfluorononenyl ether, and the reaction equation is as follows:

[0012]

[0013] The method comprises the following steps: in the presence of a phase transfer catalyst, using a KOH aqueous solution as a base, adding a hydroxy compound, slowly adding a hexafluoropropylene trimer to react, and separating and purifying to obtain perfluorononenyl ether.

[0014] Preferably, the hexafluoropropylene trimer is added dropwise within 1-2 hours.

[0015] Preferably, the phase transfer catalyst is selected from at least one of quaternary ammonium salts, quaternary phosphonium salts, polyethers, crown ethers and tertiary amines.

[0016] Preferably, the quaternary ammonium salt is selected from at least one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride and tetradecyltrimethylammonium chloride.

[0017] Preferably, the quaternary phosphonium salt is selected from (C6H5)4P + ·X - C 16 H 38 (C4H9)3P + ·X - At least one of .

[0018] Preferably, the polyether is selected from at least one of chain polyethylene glycol and chain polyethylene glycol dialkyl ether.

[0019] Preferably, the crown ether is selected from at least one of 18-crown-6, 15-crown-5, dibenzo-18-crown-6, dicyclohexane-18-crown-6, acetone furan crown ether and cyclodextrin.

[0020] Preferably, the tertiary amine is selected from at least one of R4N X, pyridine and tributylamine.

[0021] Further preferably, the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, chain polyethylene glycol, 18-crown-6, and 15-crown-5; more preferably, the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, chain polyethylene glycol, and 18-crown-6.

[0022] Preferably, the phase transfer catalyst may be 0.1%-10% of the molar amount of the hexafluoropropylene trimer; further preferably, the phase transfer catalyst may be 0.1%-5% of the molar amount of the hexafluoropropylene trimer; more preferably, the phase transfer catalyst may be 0.5%-2% of the molar amount of the hexafluoropropylene trimer.

[0023] Preferably, the molar ratio of KOH in the KOH aqueous solution to the hexafluoropropylene trimer may be 1.5-2:1; further preferably, the molar ratio of KOH in the KOH aqueous solution to the hexafluoropropylene trimer may be 1.6:1.

[0024] Preferably, the concentration of the KOH aqueous solution may be 25%-40%; further preferably, the concentration of the KOH aqueous solution may be 30%.

[0025] Preferably, the hydroxy compound is selected from alcohol or phenol compounds.

[0026] Preferably, the alcohol compound is selected from at least one of methanol, ethanol, propanol and trifluoroethanol; more preferably, it can be methanol or ethanol; more preferably, it can be methanol.

[0027] Preferably, the phenolic compound is selected from phenol or p-cresol; more preferably, it may be phenol.

[0028] Preferably, the specific conditions of the reaction may be 30-50° C., 6-8 h; further preferably, the specific conditions of the reaction may be 35° C., 7 h.

[0029] Preferably, the molar ratio of the hexafluoropropylene trimer to the hydroxy compound is 1:0.9-1.2; further preferably, the molar ratio of the hexafluoropropylene trimer to the hydroxy compound is 1:1.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The preparation method of perfluorononenyl ether provided by the present invention is a green reaction system in the presence of a phase transfer catalyst, with water as a reaction medium and an inorganic base as an acid absorber, which overcomes the disadvantage of low reaction efficiency in a heterogeneous reaction process, and the perfluorononenyl ether obtained has a high yield and a high raw material conversion rate. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, purpose and effect of the present invention easy to understand, the present invention is further explained below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making creative work all belong to the protection scope of the present invention. It is worth noting that the raw materials used in the present invention are all common commercial products, and their sources are not specifically limited. The technology and scientific terms used in the embodiments have the meanings commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0033] Example 1

[0034] Add methanol (0.5 mol) and tetrabutylammonium bromide 3.22 g (0.01 mol) to 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the whole dropwise within 1-2 hours; keep the reaction warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 95.2%, the selectivity of perfluorononenyl ether is 99.5%, and the yield is 92.3%.

[0035] Example 2

[0036] Add phenol (0.5 mol) and 2.64 g (0.01 mol) of 18-crown-6 to 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the mixture within 1-2 hours; keep the mixture warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted, and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 94.8%, the selectivity of perfluorononenyl ether is 99.2%, and the yield is 92.0%.

[0037] Example 3

[0038] 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water) was added with ethanol (0.5 mol) and polyethylene glycol PEG-1000 10 g (0.01 mol), and the temperature was raised to 35°C. 225 g (0.5 mol) of hexafluoropropylene trimer was added dropwise while stirring, and the addition was completed within 1-2 hours; the reaction was kept warm for 7 hours, and the reaction was stopped when the raw material was no longer converted by monitoring the fluorine spectrum. The lower fluorine phase was separated and the crude product was collected by distillation, and the final product was obtained by rectification. The conversion rate of hexafluoropropylene trimer was 94.9%, the selectivity of perfluorononenyl ether was 99.1%, and the yield was 91.9%.

[0039] Example 4

[0040] 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water) was added with p-cresol (0.5 mol) and 1.61 g tetrabutylammonium bromide (0.005 mol), and the temperature was raised to 35°C. 225 g (0.5 mol) of hexafluoropropylene trimer was added dropwise while stirring. The addition was completed within 1-2 hours. The reaction was kept warm for 7 hours, and the reaction was stopped when the raw material was no longer converted by monitoring the fluorine spectrum. The lower fluorine phase was separated and the crude product was collected by distillation, and the final product was obtained by rectification. The conversion rate of hexafluoropropylene trimer was 94.7%, the selectivity of perfluorononenyl ether was 98.9%, and the yield was 91.5%.

[0041] Example 5

[0042] Add methanol (0.5 mol) and tetrabutylammonium bromide 0.644 g (0.002 mol) to 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the whole dropwise within 1-2 hours; keep the reaction warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 93.4%, the selectivity of perfluorononenyl ether is 98.1%, and the yield is 91.2%.

[0043] Comparative Example 1

[0044] Add methanol (0.5 mol) to 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the whole amount within 1-2 hours; keep the reaction warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 56.2%, the selectivity of perfluorononenyl ether is 58%, and the yield is 56%.

[0045] Comparative Example 2

[0046] Add propanol (0.5 mol) to 1.5 mol of 30% KOH aqueous solution (prepared by dissolving 84 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the whole amount within 1-2 hours; keep the reaction warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 58.6%, the selectivity of perfluorononenyl ether is 60%, and the yield is 58%.

[0047] Comparative Example 3

[0048] Add methanol (0.5 mol) and 32.2 g (0.1 mol) of tetrabutylammonium bromide to 0.8 mol of 30% KOH aqueous solution (prepared by dissolving 45 g KOH in 105 g water), heat to 35°C, add 225 g (0.5 mol) of hexafluoropropylene trimer dropwise while stirring, and add the whole amount within 1-2 hours; keep the reaction warm for 7 hours, monitor the reaction by fluorine spectrum until the raw material is no longer converted and stop the reaction. Separate the lower fluorine phase, distill and collect the crude product, and obtain the final product by rectification. The conversion rate of hexafluoropropylene trimer is 76.2%, the selectivity of perfluorononenyl ether is 79%, and the yield is 78.5%.

[0049] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing perfluorononenyl ether, characterized in that: The method comprises the following steps: in the presence of a phase transfer catalyst, using a KOH aqueous solution as a base, adding a hydroxy compound, slowly adding a hexafluoropropylene trimer to react, and separating and purifying to obtain a perfluorononenyl ether; The phase transfer catalyst is 0.5%-2% of the molar amount of hexafluoropropylene trimer; The molar ratio of KOH to hexafluoropropylene trimer in the KOH aqueous solution is 1.5-2:1; The phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, chain polyethylene glycol, and 18-crown-6; The hydroxy compound is an alcohol or a phenol compound; the alcohol compound is selected from at least one of methanol and ethanol; the phenol compound is selected from phenol or p-cresol; The hexafluoropropylene trimer is added dropwise within 1-2 hours.

2. The preparation method according to claim 1, characterized in that: The concentration of the KOH aqueous solution is 25%-40%.

3. The preparation method according to claim 1, characterized in that: The specific conditions of the reaction are 30-50°C, 6-8h.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the hexafluoropropylene trimer to the hydroxy compound is 1:0.9-1.2.

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